Project Summary/Abstract Over 1.7 million persons sustain a traumatic brain injury (TBI) in the U.S. alone. Current diagnostic techniques for TBI are excellent in detecting gross morphological alterations (i.e. hemorrhagic events, changes in water content, or the emergence of anisotropic tissue densities), however, they do little to detect the immediate molecular/cellular alterations. Moreover, current treatment modalities for TBI focus on minimizing the secondary symptoms and complications associated with TBI; however, no clinical treatments currently exist to treat the underlying neuropathology for any level of injury severity ranging from mild to severe. Therefore, there is an obvious need to develop diagnostic and therapeutic (theranostic) intervention strategies that recognize and exploit the molecular pathological events. The long-term goal of this project is develop theranostic platform technologies that exploit pathological signatures of neural injury at the molecular level. To achieve this goal, the primary objective of this proposal is to demonstrate the utility of single chain antibody fragments (nanobodies) that recognize and exploit the heterogeneous injury microenvironment as targeting motifs for nanoscale targeted probes. The rationale for the proposed research is that nanobody probes developed to recognize the complexity of the neural injury environment at the molecular level will significantly enhance the sensitivity of future theranostic modalities for TBI. This objective will be realized through the pioneering nanotechnology platform that will be based on unique nanobodies identified with complex phage biopanning assays against molecular targets that are prevalent during various stages of the injury sequelae (e.g. fibrin, reactive astrocytes, degenerative neurons). This platform will then be employed to explore the following approaches to address current limitations in current diagnostic and therapeutic interventions. Approaches: 1. Exploit pathological signatures at the cellular/molecular level to develop targeting contrast agents for dual imaging modalities, 2. Provide localized temporal deliver of multiple therapeutics to address the progression of TBI pathology, and 3. Redecorate injury extracellular landscape to promote and support neural regeneration within the injury penumbra. The proposed research platform is innovative because it exploits the conformational recognition of the epitope/antigen interaction to develop nano-scaled probes with specificity to the complex neural injury environment. This contribution is significant because the technology developed in this proposal has the potential to revolutionize the approach for TBI theranostics.